Hat tip Miss Cellania:
I would like to add this. Some devices that are meant to replace a knife may save you time when you chop the food item but then, can't be put in the dishwasher and have to be cleaned with a tiny toothbrush or something which takes way longer than the time you saved.
Great marketing is when the word "SHAM" is in the name of your product.
The last time I checked, I had no problems putting a Slap-Chop style device in the dishwasher. The thing to check for is if it opens up to expose the blades.
Rick you are probably right but I guarantee that the instructions say don't do that.
(UPDATE: Documentation added above.)
I will admit I purchased a Slap Chop at my local hardware store. It isn't the universal chopper it is advertised to be, but it does come in handy for chopping things into tiny pieces that would otherwise be difficult to control on the board. I've used it to finely chop onions, peppers, carrots, and nuts. And if you're just using it for vegetables, you can disassemble it and rinse it off and it's clean. When you do need to wash it, it's probably no more trouble to clean than a food processor (which I don't have).
But a knife, you just wipe on your shirt or lick off. Depending.
I make no claim that the one my mother has is that particular brand, (in fact, I'm pretty sure it isn't).
I have never used the Slap Chop. However, I have generally had poor experiences with as-seen-on-tv kitchenware items. They tend to be of low quality manufacture, which has two problems. First, you cannot put as much force into them without breaking them, which limits their usefulness. Second, they wear out rapidly.
Other problems include bulkiness (many of these things are difficult to store) and lack of usefulness for other tasks. A knife is smaller and more versatile. And a really good knife will last you a lifetime if you take proper care of it. (Note: this does mean handwashing, so you don't ruin the edge with the abrasive detergents in a dishwasher.)
And then there is the issue that many of these tools provide only a marginal benefit over tools you may already own. It's hilarious how incompetent the actors in many of the commercials have to be in order to make the tool look indespensible. ;-) Most recently, I've had to laugh at the revolutionary new pan for making filled pancakes. It's so revolutionary that my mom has a cast-iron one that belonged to her grandmother. Ebelskeivers are not actually a recent invention. ;-)